1. Field of the Invention
The present invention relates to promoters and their use in transgenetic plants.
It is possible to genetically alter crop plants by molecular biology methods, and to express proteins specifically. For this, the selection of a suitable promoter is of considerable relevance. Therefore, a great need for well-characterized promoters with specific characteristics exists.
2. Description of the Related Art
During the last years, a large number of plant promoters was isolated and analyzed for their effect. In the meantime, octopine synthase (ocs), nopaline synthase (nos) and mannopine synthase (mas) isolated from Agrobacterium tumefaciens and TR promoters (De Greve et al., 1982, Depicker et al., 1982; Velten et al., 1984) and 35S promoter of cauliflower mosaic virus (Odell et al., 1985) respectively, have found a broad application. Plant promoters with a constitutive activity have been described for tobacco (WO 97/28268) and raspberry (WO 97/27307).
Organ, tissue or cell specific promoters can be used for the expression of genes in specific plant parts. Specificity in this context can mean, that a promoter is mainly or exclusively active in one organ, tissue or cell type. Mainly active in a particular organ are, e.g. the tomato promoters TFM7 and TFM9 in tomato fruits (U.S. Pat. No. 5,608,150), a brassica promoter in roots (WO 94/02619), a sun flower promoter in seeds (WO 98/45460) and a potato promoter (WO 98/18940) in leaves. These promoters show their highest activity in the mentioned organs. An exclusive activity for a certain compartment was described for a guard cell specific promoter of potato (DE 42 07358 A1) for the tapetum specific promoter TA29 from tobacco (EP 0 344 029 B1) and for the pistil and pollen specific SLG promoter from brassica (Dzelzkalns et al., 1993).
From sugar beet, an organ specific promoter is known, which is mainly active in the storage root tissue of sugar beet (WO 97/32027). However, this promoter of the sucrose synthase gene is not only active in roots but also, with less activity, in other tissues like leaves (Hesse and Willmitzer, 1996).